1. Field of the Invention
The present invention relates to an optical film containing a new polymer having a naphthyl group.
2. Description of the Related Art
A liquid crystal display device (hereinafter referred to as LCD) is an element for displaying characters and images by utilizing electrooptical properties of a liquid crystal molecule, and spreads widely in portable telephones, notebook computers and liquid crystal televisions. However, LCD utilizes a liquid crystal molecule having optical anisotropy, so that there is a problem that excellent display properties are exhibited in one direction, while a screen becomes dark and unclear in other directions. A retardation film is widely adopted for LCD to solve such a problem. One retardation film has conventionally been developed, which has properties (also called inverse wavelength dispersion properties) such that higher retardation value is offered in measuring by light with longer wavelength (see Japanese Unexamined Patent Publication No. 2002-221622). However, a conventional retardation film exhibiting inverse wavelength dispersion properties is as high as 200° C. or more in glass transition temperature and very fragile, so that processability such as drawing is poor. Also, there is room for improving wavelength dispersion properties of a retardation film. Thus, the solution of the problems has been desired.